The major flaw in your analysis is that merely covering your mortgage is the absolute worst possible metric of a successful real estate investment. Remember that when most of us evaluate a rental, we're looking for expenses to be ~50% of collected rents (which can vary somewhat, but over long time horizons tends to be approximately true), then to cover mortgage, and to cash flow beyond that a few hundred bucks per unit. That would be the rough definition of a "acceptable" deal, which excellent deals available that go far beyond that (2% or more of purchase price every month in rent would be a pretty great deal).
Think about when we evaluate someone's investments in funds-- If they said "but I've averaged 4-5% annually for the past 20 years! I've beaten inflation!" We would shake our heads and point to the fact that with a low expense ratio fund, they would have averaged 8-11% over that same time period. In the absolute ideal scenario of your rental, where absolutely, miraculously, nothing breaks, you get the mortgage paid for you. But is that objectively a good investment when the same amount of equity could be built, a healthy margin for repairs, vacancy, and property management if you decided to move could build up, and you could pocket a few hundred bucks a month on top of all that? Your current rental is a poor use of resources when evaluated against other rentals.
